Archive for June, 2009

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Safety measures for Plasma Cutter

Tuesday, June 30th, 2009

Before starting the plasma cutting work a welding operator has to keep certain things in mind: Always wear safety glasses, protective clothing, oil free leather gloves, welding mask and welding helmet before starting your plasma cutting work. Sturdy footwear with rubber soles must be worn. Respiratory protection devices may be required for some operations.

Make sure that the working area is clean and clear of grease, oil and any flammable materials. Wear leather boots to protect your feet. Do not keep matches or lighters in your pockets or anywhere in the work area. Keep the torch tip of your plasma cutter pointed away from you at all times.

A person can get electric shock while using a plasma cutter if he does not follow certain precautionary steps. A person can get electric shock by two reasons. A welding operator can suffer a primary voltage shock or a secondary voltage shock. Primary voltage shock (i.e.230, 460 volts) is the most serious danger because it is much greater than secondary voltage shock (i.e. 60-100 volts). A welding operator gets primary voltage shock while touching a lead inside the welding power source while you have your body or hand in contact with the welder case or other grounded metal. Turning the equipment’s power switch off does not turn power off inside the case. Never remove panels without unplugging the input power cord or turning the power disconnect switch off. Secondary voltage shock comes from touching part of the welding circuit, such as a bare spot on the electrode cable, while also touching the grounded metal work piece. Avoid touching both parts of a circuit at the same time.

When both electricity and compressed air forms a hot plasma arc while cutting various metals, lot of gasses are released due to heated metals. Do not breathe them in. These gases can cause chronic health effects if proper steps are not taken. Respiratory protection devices may be required for some operations. Ventilate the welding area with an exhaust hood positioned on the plasma arc to maintain a safe breathing area.

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How to Tig Weld?

Monday, June 29th, 2009

Gas tungsten arc welding (GTAW) also known as tungsten inert gas
(TIG) welding, is an arc welding process that uses a non consumable tungsten electrode to produce the weld. The welded area is protected from getting contaminated with the help of shielding gas and a filler metal such as aluminum or stainless steel. Gas tungsten arc welding can weld stainless steel and light nonferrous materials like aluminum and magnesium. Tungsten inert gas does stronger and higher quality welds when compared to its competing procedures like shielded metal arc and gas metal arc welding. Tig welding is complicated, difficult and much slower than other welding procedures like mig or arc welding.

Manual tig welding is considered most difficult among all the welding procedures in the industry. Because welding operator has to maintain a short arc length, make sure that great care and skill are required to prevent contact between the electrode and the work piece. TIG Welding generally requires two hands because the welder manually feeds a filler metal into the weld area with one hand while manipulating the welding torch in the other.

In the beginning, tig welding may be considered complex and difficult task but through regular practice and tuition it becomes easy for the welding operator to perform the task. In tig welding, very less cleaning is required, the finished weld is neat & tidy allowing an artistic feel to the work. Major examples of quality tig welds are bicycle frames, marine fittings, interior kitchen fittings and steel artwork.

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What is Resistance Spot Welding?

Friday, June 26th, 2009

Spot welding means joining two or more metals parts together with the help of heat and pressure. It is considered one of the oldest welding processes. This type of welding can be used to weld thin or thick foils but cannot be used for above about 6 mm thickness. High quality welds can also be made in stainless steels, nickel alloys, aluminum alloys and titanium.

Resistance spot welding produces little fumes and very less arc rays. Danger of flying sparks is less when compared to other processes. But tongs and linkages can cause higher risk of mechanical hazards such as pinching and crushing the fingers and hands.

Resistance is the opposition that a substance offers to the flow of electric current. If the metal has lesser resistance, less heat is generated when current passes through it. The higher the resistance of a metal, the more heat is generated when the same current passes through it. If you want best results in resistance welding you should have a detailed understanding of the materials being welded, careful control of the heat and pressure at the weld point, and consideration of numerous other factors.

Benefits of Resistance Welding

  • High speed welding
  • Easily automated
  • Suitable for high rate production
  • Economical
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Safety Measures to be Followed While Doing Resistance Spot Welding

Thursday, June 25th, 2009

Spot Welding can lead to fire, burns or explosions

  • Flying sparks, hot equipment or hot work piece can cause fire or burns. Protect yourself from sparks and hot metal.
  • Welding sparks can move to small cracks easily. Be alert while welding.
  • Always keep a fire extinguisher in the welding room.
  • Avoid spot welding in closed containers.
  • Once your welding work is over, make sure that the area is free of sparks and flames.
  • Make sure you use correct circuit breakers.

Electric shock can cause severe burns to the skin or kill a person

  • See to it that you do not touch any electrical equipment while it is on.
  • Always wear welding gloves and protection clothes while spot welding.
  • Turn off all the electrical equipments when not in use.
  • Make sure all the electrical equipments are well maintained. In case
    of any repairs rectify it at once.
  • Make sure you keep all panels and guards in a protected place.

Sparks can burn or injure eyes and skin

  • Always wear face shield or safety goggles while welding.
  • Wear protective clothes like heavy shirt, cuff less trousers, high shoes, leather gloves and a cap while welding.
  • Avoid clothing made of synthetic materials.
  • Protect your eyes and face by wearing a welding helmet.

Wear gloves while working with Hot metals

  • Make sure you wear insulated gloves while using this equipment.
  • Avoid touching tips, tongs with bare hands.
  • Cool tongs and tips before touching.

Moving parts like tongs, tips and linkages can injure fingers and hands

  • Be away from moving parts and pinch points.
  • Avoid putting hands between tips.

Cleaners, paints and plating can cause fumes which are hazardous

  • Avoid breathing these fumes.
  • If inside, ventilate the area to remove fumes.
  • In limited space, always keep a respirator.
  • Always read the manufacturer’s manual carefully.
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Have a Great Career in Welding?

Wednesday, June 24th, 2009

In a welding career you can get jobs in robotics, construction etc. A welder can earn from $15 per hour to $100 and beyond. Welding means join metal parts permanently. Welding can join beams when constructing buildings, bridges and other structures. Welder uses his skills for building automobiles, ships and in many manufacturing companies. If you have completed your high school and had some vocational training you can become a welder. If you have done your post graduation it will help you in getting better jobs. You should be good in mathematics if you want a career in welding. Welding operators should know about geometry and about angles, how to use compass and protractors. He should also have basic math skills like addition, subtraction and fraction.

The certified welder program is a performance-based program with no prerequisite courses of certification required. Final certification is being accepted universally. Welding operators need good vision and manual dexterity. They should be able to work for long hours even in uncomfortable positions. It is important that they get additional training and perform tasks in other production jobs. There is a good demand for qualified welders as they are in limited supply. Manufacturing industry employs most welding workers.

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Points to Remember Before Buying a Welding Helmet

Tuesday, June 23rd, 2009

Welding is the process of joining metals by melting the parts and then using a filler to form a joint. Welding can be done with a gas flame or electric arc or ultrasound. Welding is an unsafe task. A Welding operator should protect himself while welding. He should wear certain safety equipments like protective clothes, welding helmets, gloves etc. A welding helmet can protect your eyes from ultraviolet and infrared rays. While buying a welding helmet you have to look into certain features:

Always buy a welding helmet that is lightweight and comfortable to wear. If a welding operator is uncomfortable wearing a welding helmet it may lead to accidents. Welding shields must block ultraviolet and infrared rays to be effective. If an operator wears light weight helmet it can minimize strain on its neck and reduces fatigue.

Auto darkening welding helmets have lenses that automatically darken when a welding arc is struck and returns to a light state when welding ceases, it allows the wearer to work without removing the helmet. Passive welding helmets are available in fiberglass, leather, plastic, thermoplastic, vulcanized fiber in various colors and helmet types.

Solar power and battery life welding helmets:

Auto darkening helmets generally have non-replaceable battery and solar assist panel. While using this helmet for the first time you should charge it for sometime in front of direct sunlight. A better investment is a helmet powered by a replaceable battery and solar assist panel that enables you to start welding right away.

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Aluminum Welding

Monday, June 22nd, 2009

Some of the factors that affect the welding of aluminum are

  • Aluminum Oxide coating
  • Thermal conductivity
  • Thermal expansion Coefficient
  • Low melting temperature

Melting point of Aluminum oxide is nearly 1926 ° C. As the aluminum oxide film becomes thicker, it will start absorbing moisture from the air. Moisture is a source of hydrogen which is the cause of porosity in aluminum welds. Hydrogen can come from oil, paint, dirt, base metal, oxide, etc. Hydrogen will enter the weld pool and is soluble in molten aluminum. Hydrogen is rejected during solidification. Prior to welding, aluminum oxide film must be removed. If not, it may lead to reduction in ductility, lack of fusion and weld cracking.

Aluminum has a thermal conductivity which is about six times as fast as steel, which means more heat has to be put into aluminum even when the melting point is less than half that of steel.

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Safety Steps To Be Followed While Arc Welding

Friday, June 19th, 2009

A student should know the dangers of arc welding before he/she starts it. The two factors that can lead to burns are high temperature arc and hot metal. Electric arc provides two types of rays like ultra violet and infra-red which can cause very severe burns to the eyes in a short period of time. Welding operator should always wear a helmet and other protective devices while welding so that he can protect himself from harmful rays. Filter plates in the welding helmet will remove 99% of the harmful rays if proper shade lens is used.

Electric shock and Harmful flames are other dangers associated with arc welding. Welding operator can get electric shock if he welds without gloves, bare cables, uninsulated holder etc. A welding operator should take all safety precautionary steps to protect him against any hazards. He can protect himself by wearing protective clothes, working in dry conditions, provide adequate ventilation etc.

There is a list of safety precautionary steps which a welding operator should be similar before arc welding:

Make sure you always wear leather gloves, cables are in good condition, electrode holders are properly insulated while welding. Do not stand on wet areas while welding. Wear safety glasses to protect your eyes and face. Wear protective clothing, leather gloves and high top shoes while welding. Handle hot metal with pliers or tongs. Keep electrode stubs properly disposed of. Always use a helmet with the correct shade lens while welding. Try working in ventilated areas. See to it that you have breathing devices in the working area. Never weld near inflammable materials.

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Different Types of TIG Welding Joints

Thursday, June 18th, 2009

The different types of joints used for TIG welding are as follows:

Butt Joint:

Square-edge butt joint can be easily prepared and welded without filler rod. This Butt joint is mostly preferred for lighter materials. If you want to weld without filler rod, see to it that you avoid burning through the metal. Single-V butt joints are mostly used in materials that have thickness ranging from 3/8” to 1/2” to secure complete penetration. Double-V butt joint is preferable in metal that exceeds ½” thickness. Welding can be done on both sides.

Lap Joint:

Lap Joints are mostly preferred for metals that are ¼” or less in thickness. It can be welded with or without filler rod. This joint is not preferred for metals that exceed ¼” in thickness.

Corner Joint:

Filler rod is not required in corner joint on lighter metals that is upto 1/8” in thickness. But for heavy metals filler rod is required.

T-Joint:

A T-joint can be formed by inserting a piece of metal perpendicular to another to form a T-shape. Filler rod is very important to weld T-joints despite thickness of metal.

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TIG Welding Overview

Wednesday, June 17th, 2009

In the TIG (tungsten inert gas) welding process, an essentially non-consumable tungsten electrode is used to provide an electric arc for welding. A sheath of inert gas surrounds the electrode, the arc, and the area to be welded. This gas shielding process prevents any oxidization of the weld and allows for the production of neat, clean welds.

TIG welding differs from MIG (metal inert gas) welding in that the electrode is not consumed in the weld. In the MIG welding process the electrode is continuously melted and is added into the weld. In TIG welding, no metal is added unless a separate filler rod is used.

TIG welding can be performed with a large variety of metals. The two most commonly TIG welded metals in the PRL are steel and aluminum. Steel is relatively easy to TIG weld and it is possible to produce very tight, neat welds. Aluminum takes a little more skill, and one should have at least a little bit of experience in welding steel before making the transition to aluminum. However, the basic technique is essentially the same and most people can make the jump to aluminum fairly easily.

TIG welding is an extremely powerful tool. With a little practice, it is possible to make beautiful welds much more quickly and easily than with oxy-acetylene welding. It also the only option currently available in the shop for welding aluminum.

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